Research work "Bacteria: harmful and beneficial". good and bad bacteria good and bad bacteria

In addition to harmful, there are beneficial bacteria that provide the body with great help.

For the layman, the term "bacteria" is most often associated with something harmful and life-threatening.

Most often, among the beneficial bacteria, sour-milk microorganisms are recalled.

If we talk about harmful bacteria, then people most often remember such diseases as:

dysbacteriosis;
plague;
dysentery and some others.

Beneficial bacteria for humans help to carry out some biochemical processes in the body that ensure normal life.

Bacterial microorganisms live almost everywhere. They are found in air, water, soil, in any type of tissue, both living and dead.

A harmful microorganism can cause serious harm to the body, and the resulting pathologies can seriously undermine the state of health.

The list of the most famous pathogenic microbes includes:

Salmonella.
Staphylococcus.
Streptococcus.
Vibrio cholerae.
Plague wand and some others.

If harmful microorganisms are known to most people, then not everyone knows about beneficial bacterial microorganisms, and those people who have heard about the presence of beneficial bacteria are unlikely to be able to name them and how they are useful to humans.

Depending on the impact on humans, the microflora can be divided into three groups of microorganisms:

pathogenic;
conditionally pathogenic;
non-pathogenic.

Non-pathogenic microorganisms are the most useful for humans, pathogenic ones are the most harmful, and conditionally pathogenic microorganisms can be beneficial under certain conditions, and become harmful when external conditions change.

In the body, beneficial and harmful bacteria are in balance, but when some factors change, the predominance of pathogenic flora can be observed, which leads to the development of various ailments.

Beneficial bacteria for humans

The most useful for the human body are sour-milk and bifidobacteria.

These types of bacteria are not capable of leading to the development of diseases in the body.

Beneficial bacteria for the intestines are a group of lactic acid bacteria and bifidobacteria.

Beneficial microbes - lactic acid bacteria are used in the production of a variety of products from milk. In addition, they can be used in the preparation of dough and some other types of products.

Bifidobacteria form the basis of the intestinal flora in the human body. In young breastfed children, this type of microorganism accounts for up to 90% of all types of bacteria living in the intestines.

These bacteria are entrusted with the performance of a large number of functions, the main among which are the following:

Ensuring the physiological protection of the digestive tract from penetration and damage by pathogenic microflora.
Provides the production of organic acids. Preventing the reproduction of pathogenic organisms.
They participate in the synthesis of B vitamins and vitamin K, in addition, they participate in the process of protein synthesis necessary for the human body.
Accelerates the absorption of vitamin D.

Bacteria useful to humans perform a huge number of functions and their role is difficult to overestimate. Without their participation, it is impossible to carry out normal digestion and absorption of nutrients.

The colonization of the intestines with beneficial bacteria occurs in the first days of a baby's life.

Bacteria enter the baby's stomach and begin to participate in all the digestive processes that occur in the body of the newborn.

In addition to fermented milk and bifidobacteria, E. coli, streptomycetes, mycorrhiza and cyanobacteria are useful for humans.

These groups of organisms play a huge role in human life. Some of them prevent the development of infectious diseases, others are used in drug production technologies, and still others ensure balance in the planet's ecological system.

The third type of microbes are Azotobacteria, their impact on the environment is difficult to overestimate.

Characteristics of sour milk stick

The lactic acid microbes are rod-shaped and Gram-positive.

The habitat of various microbes of this group is milk, dairy products such as yogurt, kefir, they also multiply in fermented foods and are part of the microflora of the intestines, mouth and female vagina. If the microflora is disturbed, thrush and some dangerous diseases can develop. The most common species of these microorganisms are L. acidophilus, L. reuteri, L. Plantarum and some others.

This group of microorganisms is known for its ability to use lactose for life and produce lactic acid as a by-product.

This ability of bacteria is used in the production of products that require fermentation. With the help of this process, it is possible to produce such a product from milk as yogurt. In addition, fermented milk organisms can be used in the salting process. This is due to the fact that lactic acid can act as a preservative.

In humans, lactic acid bacteria are involved in the process of digestion, ensuring the breakdown of lactose.

The acidic environment that occurs during the life of these bacteria prevents the development of pathogenic microflora in the intestine.

For this reason, lactic acid bacteria are an important component of probiotic preparations and dietary supplements.

Reviews of people using such drugs and dietary supplements to restore the microflora of the gastrointestinal tract indicate that these medicines have a high degree of effectiveness.

Brief description of bifidobacteria and Escherichia coli

This variety of microorganisms belongs to the group of gram-positive. They are branched and rod-shaped.

The habitat of this type of microbes is the human gastrointestinal tract.

This type of microflora is capable of producing acetic acid in addition to lactic acid.

This compound inhibits the growth of pathogenic microflora. The production of these compounds contributes to the control of pH levels in the stomach and intestines.

Such a representative as the B. Longum bacterium ensures the destruction of indigestible plant polymers.

Microorganisms B. longum and B. Infantis in the course of their activity produce compounds that prevent the development of diarrhea, candidiasis and fungal infections in infants and children.

Due to the presence of these beneficial properties, this type of microbe is often included in the composition of tablets sold in pharmacies of probiotic medicines.

Bifidobacteria are used in the production of various lactic acid products, such as yogurt, ryazhenka, and some others. Being in the gastrointestinal tract, they act as purifiers of the intestinal environment from harmful microflora.

The composition of the microflora of the gastrointestinal tract also includes Escherichia coli. She takes an active part in the processes of digestion of food. In addition, they are involved in some processes that ensure the vital activity of the cells of the body.

Some varieties of the stick are capable of causing poisoning in case of excessive development. Diarrhea and kidney failure.

Brief description of streptomycetes, nodule bacteria and cyanobacteria

Streptomycetes in nature live in soil, water and the remains of decaying organic matter.

These microbes are Gram-positive and filamentous under the microscope.

Most streptomycetes play a crucial role in maintaining the ecological balance in nature. Due to the fact that these microbes have the ability to process decaying organic matter, it is considered as a biorestorative agent.

Some types of streptomycetes are used to make effective antibiotics and antifungal drugs.

Mycorrhiza live in the soil, they exist in the roots of plants, entering into symbiosis with the plant. The most common symbiont of mycorrhiza are plants of the legume family.

Their benefit lies in the ability to bind atmospheric nitrogen, converting it in compounds into a form that is easily absorbed by plants.

Plants are not able to assimilate atmospheric nitrogen, so they are entirely dependent on the activity of this type of microorganism.

Cyanobacteria live most often in water and on the surface of bare rocks.

This group of living organisms are known as blue-green algae. This type of living organisms play an important role in wildlife. They are responsible for the fixation of atmospheric nitrogen in the aquatic environment.

The presence of such abilities in these bacteria as calcification and decalcification make them an essential component of the system for maintaining the ecological balance in nature.

Microorganisms harmful to humans

Pathogenic representatives of microflora are microbes capable of provoking the development of various ailments in the human body.

Some types of microbes can provoke the development of deadly diseases.

Very often, such diseases can be transmitted from an infected person to a healthy person. In addition, a large number of pathogenic microflora can spoil food.

Representatives of pathogenic microflora can be gram-positive, gram-negative and rod-shaped microbes.

The table below shows the most famous representatives of the microflora.

Name	Habitat	Harm to humans
Mycobacteria	Live in water and soil	Able to provoke the development of tuberculosis, leprosy and ulcers
tetanus bacillus	Lives on the surface of the skin in the soil layer and in the digestive tract	Provoke the development of tetanus, muscle spasms and the occurrence of respiratory failure
Plague wand	Able to live only in humans, rodents and mammals	Can cause bubonic plague, pneumonia and skin infections
Helicobacter pylori	Able to develop on the gastric mucosa	Provokes the development of gastritis, peptic ulcer, produce cytotoxins and ammonia
anthrax bacillus	Lives in the soil layer	Causes anthrax
botulism stick	Develops in foodstuffs and on the surface of contaminated utensils	Contributes to the development of severe poisoning

Pathogenic microflora can develop in the body for a long time and feed on useful substances, weakening its condition, which leads to the development of various infectious diseases.

The most dangerous bacteria for humans

One of the most dangerous and resistant bacteria is a bacterium called Staphylococcus aureus. In the ranking of dangerous bacteria, it can rightfully take a prize.

This microbe is capable of provoking the development of several infectious diseases in the body.

Some varieties of this microflora are resistant to the strongest antibiotics and antiseptics.

Varieties of Staphylococcus aureus are able to live:

in the upper parts of the human respiratory system;
on the surface of open wounds;
In the channels of the urinary organs.

For a human body with a strong immune system, this microbe is not dangerous, but if the body is weakened, it can manifest itself in all its glory.

The bacteria called Salmonella typhi are very dangerous. They are able to provoke the appearance of such a terrible and deadly infection in the body as typhoid fever, in addition, acute intestinal infections can develop.

The specified pathological flora is dangerous for the human body in that they produce toxic compounds that are very dangerous to health.

Poisoning by these compounds of the body can provoke the appearance of serious and fatal diseases.

Where do bacteria live in the human body?

Most of them inhabit the intestines, providing a harmonious microflora.
They live on mucous membranes, including in the oral cavity.
Many microorganisms inhabit the skin.

What are microorganisms responsible for?

They support immune function. With a lack of beneficial microbes, the body is immediately attacked by harmful ones.
By feeding on the components of plant foods, bacteria help digestion. Most of the food that reaches the large intestine is digested thanks to bacteria.
Benefits of intestinal microorganisms - in the synthesis of B vitamins, antibodies, absorption of fatty acids.
The microbiota maintains the water-salt balance.
Bacteria on the skin protect the integument from the penetration of harmful microorganisms into them. The same applies to the population of mucous membranes.

What happens if you remove bacteria from the human body? Vitamins will not be absorbed, hemoglobin will fall in the blood, diseases of the skin, gastrointestinal tract, respiratory organs, etc. will begin to progress. Conclusion: the main function of bacteria in the human body is protective. Let's take a closer look at what types of microorganisms exist and how to support their work.

Major groups of beneficial bacteria

Good bacteria for humans can be divided into 4 main groups:

bifidobacteria;
lactobacilli;
enterococci;
coli.

The most abundant beneficial microbiota. The task is to create an acidic environment in the intestines. In such conditions, pathogenic microflora cannot survive. Bacteria produce lactic acid and acetate. Thus, the intestinal tract is not afraid of the processes of fermentation and decay.

Another property of bifidobacteria is antitumor. Microorganisms are involved in the synthesis of vitamin C - the main antioxidant in the body. Vitamins D and B-group are absorbed thanks to this type of microbe. The digestion of carbohydrates is also accelerated. Bifidobacteria increase the ability of the intestinal walls to absorb valuable substances, including calcium, magnesium and iron ions.

Lactobacilli live in the digestive tract from the mouth to the large intestine. The joint action of these bacteria and other microorganisms controls the reproduction of pathogenic microflora. Intestinal pathogens are much less likely to infect the system if lactobacilli inhabit it in sufficient numbers.

The task of little hard workers is to normalize the work of the intestinal tract and support immune function. The microbiota is used in the food and medical industries: from healthy kefir to preparations for the normalization of the intestinal microflora.

Lactobacilli are especially valuable for women's health: the acidic environment of the mucous membranes of the reproductive system does not allow the development of bacterial vaginosis.

Advice! Biologists say that the immune system starts in the gut. The body's ability to resist harmful bacteria depends on the condition of the tract. Keep the digestive tract normal, and then not only the absorption of food will improve, but the body's defenses will also increase.

Enterococci

The habitat of enterococci is the small intestine. They block the reproduction of pathogenic microorganisms, help to digest sucrose.

The Polzateevo magazine found out that there is an intermediate group of bacteria - conditionally pathogenic. In one state, they are beneficial, and when any conditions change, they become harmful. These include enterococci. Staphylococci living on the skin also have a dual effect: they protect the integument from harmful microbes, but they themselves are able to get into the wound and cause a pathological process.

E. coli often causes negative associations, but only some species from this group bring harm. Most Escherichia coli have a beneficial effect on the tract.

These microorganisms synthesize a number of B vitamins: folic and nicotinic acid, thiamine, riboflavin. An indirect effect of such synthesis is an improvement in the composition of the blood.

What bacteria are harmful

Harmful bacteria are more widely known than beneficial ones, as they pose a direct threat. Many people know the dangers of salmonella, plague bacillus and vibrio cholerae.

The most dangerous bacteria for humans:

Tetanus bacillus: Lives on the skin and can cause tetanus, muscle spasms, and respiratory problems.
Botulism stick. If you eat a spoiled product with this pathogen, you can earn a deadly poisoning. Botulism often develops in expired sausages and fish.
Staphylococcus aureus can cause several ailments in the body at once, is resistant to many antibiotics and adapts incredibly quickly to drugs, becoming insensitive to them.
Salmonella is the cause of acute intestinal infections, including a very dangerous disease - typhoid fever.

Prevention of dysbacteriosis

Living in an urban environment with poor ecology and nutrition significantly increases the risk of dysbacteriosis - an imbalance of bacteria in the human body. Most often, the intestines suffer from dysbacteriosis, less often the mucous membranes. Signs of a lack of beneficial bacteria: gas formation, bloating, abdominal pain, upset stool. If you start the disease, vitamin deficiency, anemia, an unpleasant smell of the mucous membranes of the reproductive system, weight loss, and skin defects may develop.

Dysbacteriosis easily develops in conditions of taking antibiotic drugs. To restore the microbiota, probiotics are prescribed - formulations with living organisms and prebiotics - preparations with substances that stimulate their development. Fermented milk drinks containing live bifidus and lactobacilli are also considered useful.

In addition to therapy, the beneficial microbiota responds well to fasting days, eating fresh fruits and vegetables, and whole grains.

The role of bacteria in nature

The kingdom of bacteria is one of the most numerous on the planet. These microscopic creatures bring benefits and harm not only to humans, but also to all other species, provide many processes in nature. Bacteria are found in the air and in the soil. Azotobacter are very useful inhabitants of the soil, which synthesize nitrogen from the air, turning it into ammonium ions. In this form, the element is easily absorbed by plants. The same microorganisms cleanse soils from heavy metals and fill them with biologically active substances.

Do not be afraid of bacteria: our body is so arranged that it cannot function normally without these tiny hard workers. If their number is normal, then the immune, digestive and a number of other functions of the body will be in order.

The word "bacteria" in most people is associated with something unpleasant and a threat to health. At best, sour-milk products are remembered. At worst - dysbacteriosis, plague, dysentery and other troubles. Bacteria are everywhere, good and bad. What can microorganisms hide?

What is bacteria

Bacteria in Greek means "stick". This name does not mean that harmful bacteria are meant.

This name was given to them because of the shape. Most of these single cells look like rods. They also come in squares, stellate cells. For a billion years, bacteria do not change their external appearance, they can only change internally. They can be mobile and immobile. Bacteria Outside, it is covered with a thin shell. This allows her to keep her shape. Inside the cell there is no nucleus, chlorophyll. There are ribosomes, vacuoles, outgrowths of the cytoplasm, protoplasm. The largest bacterium was found in 1999. It was called the "Gray Pearl of Namibia". Bacteria and bacillus mean the same thing, only they have a different origin.

Man and bacteria

The appearance of bacteria in the body

A newly born baby has a sterile intestine.

After his first breath, many microorganisms enter the body, with which he was not previously familiar. When the baby is first attached to the breast, the mother transfers beneficial bacteria with milk that will help normalize the intestinal microflora. No wonder doctors insist that the mother immediately after the birth of her child breastfeed him. They also recommend extending such feeding as long as possible.

Beneficial bacteria

Types of harmful bacteria

Harmful bacteria can cause a number of serious diseases in humans. For example, diphtheria, tonsillitis, plague and many others. They are easily transmitted from an infected person through air, food, touch. It is the harmful bacteria, whose names will be given below, that spoil food. They give off an unpleasant odor, rot and decompose, and cause disease.

Names of harmful bacteria

Titles	Habitat	Harm
Mycobacteria	food, water	tuberculosis, leprosy, ulcer
tetanus bacillus
Plague wand
Helicobacter pylori
anthrax bacillus	the soil	anthrax
botulism stick	food, contaminated dishes	poisoning

The most dangerous bacteria

One of the most resistant bacteria is methicillin. It is better known under the name "Staphylococcus aureus" (Staphylococcus aureus). can cause not one, but several infectious diseases. Some types of these bacteria are resistant to powerful antibiotics and antiseptics. Strains of this bacterium can live in the upper respiratory tract, open wounds and urinary tracts of every third inhabitant of the Earth. For a person with a strong immune system, this is not dangerous.

Harmful bacteria to humans are also pathogens called Salmonella typhi. They are the causative agents of acute intestinal infections and typhoid fever. These types of bacteria that are harmful to humans are dangerous because they produce toxic substances that are extremely life-threatening. During the course of the disease, intoxication of the body occurs, a very strong fever, rashes on the body, the liver and spleen increase. The bacterium is very resistant to various external influences. It lives well in water, on vegetables, fruits and reproduces well in milk products.

And another bacterium that can lead to the death of a person is It causes tuberculosis, which is resistant to drugs. If you do not seek help in a timely manner, a person may die.

Measures to prevent the spread of infections

The second stage is the destruction of the ways through which harmful bacteria can be transmitted. To do this, carry out appropriate propaganda among the population.

For many years, we considered microbes to be dangerous enemies that need to be disposed of, but in fact, everything is not as simple and unambiguous as we used to think.

Microbiologist from Chicago Jack Gilbert decided to find out if the microbes that inhabit our homes are so dangerous. To do this, he explored several houses, including his own.
The specialist came to the same conclusion as many modern scientists. No matter how strange and regrettable it may sound, the main source of bacteria in the house is the person himself. So the fight for the cleanliness of all items in the house is the same as fighting windmills.
Jack found that each person has their own unique set of microbes, and it is enough for them to stay indoors for several hours to leave an easily identifiable bacterial trail - like fingerprints. This discovery will undoubtedly help law enforcement agencies.
However, with regard to the domestic side of the issue, Gilbert did not find truly dangerous microorganisms in the dwellings of the twenty-first century.
According to the scientist, for so many centuries humanity has become accustomed to living in a dangerous world, when many people died from terrible diseases. When people learned about the nature of bacteria, they began to fight them. Of course, today we live in a much safer and healthier environment. But in their fight against microbes, people often go too far, forgetting that along with harmful ones, there are also useful ones.
“The causes of asthma, allergies, and many other diseases, as studies show, most likely lie in a violation of the microbial balance of the body. This imbalance has been found to be connected even with obesity, autism and schizophrenia!”, says the American scientist.
Another important point is that immediately after cleaning, the clean surface is the first to be inhabited by pathogenic microbes. That is, the more you clean and disinfect, the dirtier and more dangerous the room becomes. Of course, over time, the balance is established when good microbes take their place.
Gilbert is sure that one should not interfere so zealously in natural processes. After research, he himself got three dogs at home to help him and, most importantly, children maintain microbial diversity.

How will you react if you find out that in your body the total weight of bacteria is from 1 to 2.5 kilograms?
Most likely, this will cause surprise and shock. Most people believe that bacteria are dangerous and can cause serious harm to the life of the body. Yes, this is true, but there are, in addition to dangerous, also beneficial bacteria, moreover, vital for human health.

They exist within us, taking a huge part in various metabolic processes. Actively participate in the proper functioning of life processes, both in the internal and external environment of our body. These bacteria include bifidobacteria Rhizobium and E. coli, and many others.

Beneficial bacteria
We live in a world densely populated by bacteria. For example, in a soil layer 30 cm thick and 1 ha in area contains from 1.5 to 30 tons of bacteria. There are almost as many bacteria in each gram of fresh milk as there are people on Earth. They also live inside our body. There are hundreds of different types of bacteria in the human mouth. For every cell in the human body, there are about ten cells of bacteria living in the same body.

Of course, if all these bacteria were harmful to humans, it is unlikely that humans would be able to survive in such an environment. But it turns out that these bacteria are not only not harmful to humans, but, on the contrary, are very beneficial to them.

In a newborn child, the intestinal mucosa is sterile. With the first sip of milk, microscopic "residents" rush into the human digestive system, becoming his companions for life. They help a person digest food, produce some vitamins.

Many animals need bacteria to live. For example, plants are known to serve as food for ungulates and rodents. The bulk of any plant is fiber (cellulose). But it turns out that bacteria that live in special sections of the stomach and intestines help animals digest fiber.

We know putrefactive bacteria spoil food. But this harm that they bring to man is nothing compared to the benefits that they bring to nature as a whole. These bacteria can be called "natural orderlies". By decomposing proteins and amino acids, they support the cycle of substances in nature.

Bacteria help find uses for animal waste. From the millions of tons of liquid manure accumulated on farms, bacteria in special facilities can produce combustible "swamp gas" (methane). Toxic substances contained in the waste are neutralized, in addition, a considerable amount of fuel is produced. Similarly, bacteria purify wastewater.

All living organisms need nitrogen to make proteins. We are surrounded by real oceans of atmospheric nitrogen. But neither plants, nor animals, nor fungi can absorb nitrogen directly from the air. But this can be done by special (nitrogen-fixing) bacteria. Some plants (for example, legumes, sea buckthorn) form special “apartments” (nodules) on their roots for such bacteria. Therefore, alfalfa, peas, lupins and other legumes are often planted on poor or depleted soils so that their bacteria "feed" the soil with nitrogen.

Yogurt, cheese, sour cream, butter, kefir, sauerkraut, pickled vegetables - all these products would not exist if there were no lactic acid bacteria. Man has been using them since ancient times. By the way, curdled milk is digested three times faster than milk - in an hour the body completely digests 90% of this product. Without lactic acid bacteria, there would be no silage for livestock feed.

It is known that if you store wine for a long time, it gradually turns into vinegar. People have probably known about this since they learned how to make wine. But only in the XIX century. Louis Pasteur (see article "Louis Pasteur") established that this transformation is caused by acetic acid bacteria that have entered the wine. They use them to make vinegar.

Various bacteria help a person to make silk, produce coffee, tobacco.
One of the most promising ways to use bacteria was discovered only towards the end of the 20th century. It turns out that it is possible to introduce into the body of a bacterium the gene of some protein that a person needs (although it is completely unnecessary for a bacterium) - for example, the gene for insulin. Then the bacterium will begin to produce it. The applied science that makes such operations possible is called genetic engineering. After a long and difficult search, scientists managed to establish a bacterial "production" of this substance (insulin), which is vital for diabetics. In the future, it will probably be possible to turn bacteria into microscopic "factories" for the production of certain proteins on demand.

Margin of safety

Who lives in the gut?

"Wise" Neighbors

Permanent microflora

What are they doing?

Fickle microflora

Location in the gastrointestinal tract

The role of bacteria in nature

Participation in food chains

cyanobacteria

More than 2 kilograms of these microscopic creatures live in the human body! Moreover, most of them do not bring any harm, but live in peace and harmony with the owner of the body. But what are they for? What are the benefits and harms of bacteria to humans?

The role of bacteria living inside us

All microorganisms inhabiting a person from the inside can be divided into two categories:

Bacteria that bring tangible benefits to their host. They help a person to absorb and digest food, as well as synthesize useful vitamins. The most well-known bacterium with such properties is Escherichia coli. And the intestinal microflora is inhabited by various bacteroids, lacto- and bifidobacteria. Their benefit is to strengthen the immune system. They also reduce the risk of dangerous microbes entering. Excessive use of antibiotics or other chemicals can lead to the death of beneficial bacteria. As a result, dysbacteriosis develops (diarrhea, constipation, nausea) and the human immune system suffers.
- gonorrhea;
- whooping cough;
- diphtheria;
- cholera;
- plague and many other diseases.

Once in the body of animals, microbes again bring great harm. They become the source of infection with diseases such as anthrax and brucellosis (and many others). Eating the meat of an infected animal can cause serious harm to human health.

The importance of bacteria in various areas of life

There are many bacterial preparations that help control pests in agriculture and forestry. Some of these microscopic creatures are used for ensiling green fodder. And to purify wastewater, a special type of bacteria is used that decomposes organic residues and helps control the level of pollution of water bodies. And even in modern medicine, microorganisms are actively used for the manufacture of various vitamins, antibiotics and other drugs.

Not all bacteria are beneficial and serve the benefit of people. There are also those that harm food, cause decay of organic matter and produce poison in the process. Eating poor-quality food leads to poisoning of the body. In some cases, the result is even sad - a fatal outcome. To protect yourself and your loved ones from the harm caused by bad bacteria, as well as maintain the natural balance of beneficial creatures in the body, you must:

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Beneficial and harmful bacteria. What bacteria are the most dangerous to humans

What is bacteria

Bacteria in Greek means "stick". This name does not mean that harmful bacteria are meant. This name was given to them because of the shape. Most of these single cells look like rods. They also come in the form of triangles, squares, stellate cells. For a billion years, bacteria do not change their external appearance, they can only change internally. They can be mobile and immobile. A bacterium consists of one cell. Outside, it is covered with a thin shell. This allows her to keep her shape. Inside the cell there is no nucleus, chlorophyll. There are ribosomes, vacuoles, outgrowths of the cytoplasm, protoplasm. The largest bacterium was found in 1999. It was called the "Gray Pearl of Namibia". Bacteria and bacillus mean the same thing, only they have a different origin.

Man and bacteria

In our body, there is a constant struggle between harmful and beneficial bacteria. Through this process, a person receives protection from various infections. Various microorganisms surround us at every step. They live on clothes, they fly in the air, they are omnipresent.

The presence of bacteria in the mouth, and this is about forty thousand microorganisms, protects the gums from bleeding, from periodontal disease and even from tonsillitis. If a woman's microflora is disturbed, she may develop gynecological diseases. Compliance with the basic rules of personal hygiene will help to avoid such failures.

Human immunity depends entirely on the state of the microflora. Almost 60% of all bacteria are found in the gastrointestinal tract alone. The rest are located in the respiratory system and in the genital. About two kilograms of bacteria live in a person.

The appearance of bacteria in the body

A newly born baby has a sterile intestine. After his first breath, many microorganisms enter the body, with which he was not previously familiar. When the baby is first attached to the breast, the mother transfers beneficial bacteria with milk that will help normalize the intestinal microflora. No wonder doctors insist that the mother immediately after the birth of her child breastfeed him. They also recommend extending such feeding as long as possible.

Beneficial bacteria

Useful bacteria are: lactic acid, bifidobacteria, E. coli, streptomycents, mycorrhiza, cyanobacteria.

All of them play an important role in human life. Some of them prevent the occurrence of infections, others are used in the production of medicines, and others maintain a balance in the ecosystem of our planet.

Types of harmful bacteria

Harmful bacteria can cause a number of serious diseases in humans. For example, diphtheria, anthrax, tonsillitis, plague and many others. They are easily transmitted from an infected person through air, food, touch. It is the harmful bacteria, whose names will be given below, that spoil food. They give off an unpleasant odor, rot and decompose, and cause disease.

Bacteria can be gram-positive, gram-negative, rod-shaped.

Names of harmful bacteria

Table. Harmful bacteria for humans. Titles

Titles	Habitat	Harm
Mycobacteria	food, water	tuberculosis, leprosy, ulcer
tetanus bacillus	soil, skin, digestive tract	tetanus, muscle spasms, respiratory failure
Plague wand (considered by experts as a biological weapon)	only in humans, rodents and mammals	bubonic plague, pneumonia, skin infections
Helicobacter pylori	human stomach lining	gastritis, peptic ulcer, produces cytotoxins, ammonia
anthrax bacillus	the soil	anthrax
botulism stick	food, contaminated dishes	poisoning

Harmful bacteria are able to stay in the body for a long time and absorb useful substances from it. However, they can cause an infectious disease.

The most dangerous bacteria

One of the most resistant bacteria is methicillin. It is better known under the name "Staphylococcus aureus" (Staphylococcus aureus). This microorganism is capable of causing not one, but several infectious diseases. Some types of these bacteria are resistant to powerful antibiotics and antiseptics. Strains of this bacterium can live in the upper respiratory tract, open wounds and urinary tracts of every third inhabitant of the Earth. For a person with a strong immune system, this is not dangerous.

Clostridium tetan is also one of the most dangerous bacteria. It produces a poison called tetanus exotoxin. People who become infected with this pathogen experience terrible pain, convulsions and die very hard. The disease is called tetanus. Despite the fact that the vaccine was created back in 1890, every year on Earth 60 thousand people die from it.

And another bacterium that can lead to human death is Mycobacterium tuberculosis. It causes tuberculosis, which is resistant to drugs. If you do not seek help in a timely manner, a person may die.

Measures to prevent the spread of infections

Harmful bacteria, the names of microorganisms are studied from the student bench by physicians of all directions. Every year, healthcare is looking for new methods to prevent the spread of infections that are dangerous to human life. With the observance of preventive measures, you will not have to waste your energy on finding new ways to deal with such diseases.

To do this, it is necessary to identify the source of the infection in time, determine the circle of the sick and possible victims. It is imperative to isolate those who are infected and disinfect the source of infection.

The second stage is the destruction of the ways through which harmful bacteria can be transmitted. To do this, carry out appropriate propaganda among the population.

Food facilities, reservoirs, warehouses with food storage are taken under control.

Each person can resist harmful bacteria in every possible way strengthening their immunity. Healthy lifestyle, observance of elementary hygiene rules, self-protection during sexual contact, use of sterile disposable medical instruments and equipment, complete restriction from communication with quarantined people. When entering the epidemiological region or the focus of infection, it is necessary to strictly comply with all the requirements of the sanitary and epidemiological services. A number of infections are equated in their impact to bacteriological weapons.

Bacteria are beneficial and harmful. Bacteria in human life

Bacteria are the most numerous inhabitants of the planet Earth. They inhabited it in ancient times and continue to exist to this day. Some species have even changed little since then. Good and bad bacteria literally surround us everywhere (and even penetrate into other organisms). With a rather primitive unicellular structure, they are probably one of the most effective forms of wildlife and stand out in a special kingdom.

Margin of safety

These microorganisms, as they say, do not sink in water and do not burn in fire. Literally: withstand temperatures up to plus 90 degrees, freezing, lack of oxygen, pressure - high and low. We can say that nature has invested a huge margin of safety in them.

Bacteria beneficial and harmful to the human body

As a rule, the bacteria that inhabit our bodies in abundance are not given due attention. After all, they are so small that they seem to have no significant significance. Those who think so are largely mistaken. Bacteria useful and harmful have long and reliably “colonized” other organisms and successfully coexist with them. Yes, they cannot be seen without the help of optics, but they can benefit or harm our body.

Who lives in the gut?

Doctors say that if you put together just the bacteria that live in the intestines and weigh it, you get something like three kilograms! With such a huge army it is impossible to ignore. Many of the microorganisms continuously entered the human intestine, but only a few species find favorable conditions for living and living there. And in the process of evolution, they even formed a permanent microflora, which is designed to perform important physiological functions.

"Wise" Neighbors

Bacteria have long played an important role in human life, although until very recently, people did not know about it. They help their host in digestion and perform a number of other functions. What are these invisible neighbors?

Permanent microflora

99% of the population lives permanently in the intestines. They are ardent supporters and helpers of man.

Essential beneficial bacteria. Names: bifidobacteria and bacteroids. They are the vast majority.
Associated beneficial bacteria. Names: Escherichia coli, Enterococcus, Lactobacillus. Their number should be 1-9% of the total.

It is also necessary to know that under appropriate negative conditions, all these representatives of the intestinal flora (with the exception of bifidobacteria) can cause diseases.

What are they doing?

The main function of these bacteria is to help us in the process of digestion. It is noticed that a person with improper nutrition can develop dysbacteriosis. As a result, stagnation and poor health, constipation and other inconveniences. With the normalization of a balanced diet, the disease, as a rule, recedes.

Another function of these bacteria is watchdog. They keep track of which bacteria are beneficial. To ensure that "strangers" do not penetrate their community. If, for example, the causative agent of dysentery, Shigella Sonne, tries to enter the intestines, they kill it. However, it is worth noting that this happens only in the body of a relatively healthy person, with good immunity. Otherwise, the risk of getting sick increases significantly.

Fickle microflora

Approximately 1% in the body of a healthy individual are the so-called opportunistic microbes. They belong to the unstable microflora. Under normal conditions, they perform certain functions that do not harm a person, work for the good. But in a certain situation, they can manifest themselves as pests. These are mainly staphylococci and various kinds of fungi.

Location in the gastrointestinal tract

In fact, the entire digestive tract has a heterogeneous and unstable microflora - beneficial and harmful bacteria. The esophagus contains the same inhabitants as in the oral cavity. In the stomach there are only a few that are resistant to acid: lactobacilli, Helicobacter pylori, streptococci, fungi. In the small intestine, the microflora is also not numerous. Most bacteria are found in the large intestine. So, defecation, a person is able to allocate over 15 trillion microorganisms per day!

The role of bacteria in nature

She is also definitely great. There are several global functions, without which all life on the planet would have ceased to exist long ago. The most important is sanitation. Bacteria eat dead organisms found in nature. They, in essence, work as a kind of janitors, not allowing deposits of dead cells to accumulate. Scientifically they are called saprotrophs.

Another important role of bacteria is participation in the global circulation of substances on land and at sea. On planet Earth, all substances in the biosphere pass from one organism to another. Without some bacteria, this transition would simply be impossible. The role of bacteria is invaluable, for example, in the circulation and reproduction of such an important element as nitrogen. There are certain bacteria in the soil that convert the nitrogen in the air into nitrogenous fertilizers for plants (microorganisms live right in their roots). This symbiosis between plants and bacteria is being studied by science.

Participation in food chains

As already mentioned, bacteria are the most numerous inhabitants of the biosphere. And accordingly, they can and should participate in the food chains inherent in the nature of animals and plants. Of course, for a person, for example, bacteria are not the main part of the diet (unless they can be used as a food additive). However, there are organisms that feed on bacteria. These organisms, in turn, feed on other animals.

cyanobacteria

These blue-green algae (an outdated name for these bacteria, fundamentally wrong from a scientific point of view) are able to produce huge amounts of oxygen as a result of photosynthesis. Once upon a time, it was they who began to saturate our atmosphere with oxygen. Cyanobacteria continue to do this successfully to this day, forming a certain part of the oxygen in the modern atmosphere!

Bacteria in nature are harmful and beneficial to humans

Most people consider different bacterial organisms solely as harmful particles that can provoke the development of various pathological conditions. Nevertheless, according to scientists, the world of these organisms is very diverse. There are frankly dangerous bacteria that pose a danger to our body, but there are also useful ones - those that ensure the normal functioning of our organs and systems. Let's try to understand a little about these concepts and consider certain types of such organisms. Let's talk about bacteria in nature, harmful and beneficial to humans.

Beneficial bacteria

Scientists say that bacteria became the very first inhabitants of our large planet, and it is thanks to them that there is life on Earth now. Over the course of many millions of years, these organisms gradually adapted to the constantly changing conditions of existence, they changed their appearance and habitat. Bacteria were able to adapt to the surrounding space and were able to develop new and unique life support methods, including multiple biochemical reactions - catalysis, photosynthesis, and even seemingly simple respiration. Now bacteria coexist with human organisms, and such cooperation is distinguished by some harmony, because such organisms can bring real benefits.

After a small person is born, bacteria immediately begin to penetrate into his body. They are introduced through the respiratory tract along with air, enter the body along with breast milk, etc. The whole body is saturated with various bacteria.

Their number cannot be accurately calculated, but some scientists boldly say that the number of such organisms is comparable to the number of all cells. The digestive tract alone is home to four hundred varieties of different living bacteria. It is believed that a certain variety of them can grow only in a specific place. So lactic acid bacteria are able to grow and multiply in the intestines, others feel optimal in the oral cavity, and some others live only on the skin.

For many years of coexistence, man and such particles were able to recreate the optimal conditions for cooperation for both groups, which can be characterized as a useful symbiosis. At the same time, bacteria and our body combine their capabilities, while each side remains in the black.

Bacteria are able to collect particles of various cells on their surface, which is why the immune system does not perceive them as hostile and does not attack. However, after organs and systems are exposed to harmful viruses, beneficial bacteria rise to the defense and simply block the path of pathogens. When existing in the digestive tract, such substances also bring tangible benefits. They are engaged in the processing of leftover food, while releasing a significant amount of heat. It, in turn, is transmitted to nearby organs, and is carried throughout the body.

Deficiency of beneficial bacteria in the body or a change in their number causes the development of various pathological conditions. This situation can develop against the background of taking antibiotics, which effectively destroy both harmful and beneficial bacteria. To correct the number of beneficial bacteria, special preparations - probiotics can be consumed.

harmful bacteria

However, it is worth remembering that not all bacteria are human friends. Among them, there are enough dangerous varieties that can only bring harm. Such organisms, after penetrating into our body, cause the development of a variety of bacterial ailments. These are various colds, some varieties of pneumonia, and in addition syphilis, tetanus and other diseases, even deadly ones. There are also diseases of this type, which are transmitted by airborne droplets. This is dangerous tuberculosis, whooping cough, etc.

A significant number of ailments provoked by harmful bacteria develop due to the consumption of insufficiently high-quality food, unwashed and unprocessed vegetables and fruits, raw water, and insufficiently fried meat. You can protect yourself from such diseases by observing the norms and rules of hygiene. Examples of such dangerous diseases are dysentery, typhoid fever, etc.

Manifestations of diseases that have developed as a result of an attack of bacteria are the result of the pathological influence of poisons that these organisms produce, or that are formed against the background of their destruction. The human body is able to get rid of them thanks to the natural defense, which is based on the process of phagocytosis of bacteria by white blood cells, as well as on the immune system, which synthesizes antibodies. The latter carry out a bunch of foreign proteins and carbohydrates, and then simply eliminate them from the bloodstream.

Also, harmful bacteria can be destroyed with the help of natural and synthetic medicines, the most famous of which is penicillin. All drugs of this type are antibiotics, they differ depending on the active ingredient and on the mode of action. Some of them are able to destroy the cell membranes of bacteria, while others suspend the processes of their vital activity.

So, in nature there are a lot of bacteria that can bring benefits and harm to humans. Fortunately, the current level of development of medicine makes it possible to cope with the majority of pathological organisms of this kind.

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Benefits and harms of bacteria

The fact is that bacteria are not only harmful, but also undoubtedly beneficial. It is not for nothing that in the intestines of any organism there is a separate environment, which would do well to be isolated into an independent organ, which is called the microflora of the organism. The microflora contains a spectrum of bacteria necessary for normal life.
The role of bacteria in human life is great. Being all in the same intestine, the bacteria break down indigestible food residues in the stomach into organic and inorganic compounds. In the process, amino acids and some vitamins are extracted, which are immediately absorbed into the blood.
Bacteria are also found in dairy products - yogurt, kefir, fermented baked milk. Together with these products, microorganisms enter the gastric tract, where they help the stomach itself cope with its main task - the thorough digestion of food. It is for this reason that we always feel light after taking dairy products and do not feel discomfort in the stomach caused by pain, colic or nausea.
The role of bacteria in human life is great. Being inside the female genital organs, microorganisms create a special acid-base environment, the violation of which leads to a number of unpleasant diseases and inflammations. To maintain such an optimal environment, you need to follow the rules of personal hygiene.
The oral cavity is also full of microbes that allow you to get rid of inflammation and bleeding of the gums, sore throats and periodontal disease.
As you understand, microorganisms are inside our entire body, and it’s not worth getting rid of them so violently. The role of bacteria in human life is ambiguous, but the fact that we need these simple organisms is a hundred percent correct answer.
Drink less antibiotics, which destroy the normal cooperation between microbes and humans, which leads to serious illness.

Tanya

Benefit: Bacteria that provide measurable benefits to their host. They help a person to absorb and digest food, as well as synthesize useful vitamins. The most well-known bacterium with such properties is Escherichia coli. And the intestinal microflora is inhabited by various bacteroids, lacto- and bifidobacteria. Their benefit is to strengthen the immune system. They also reduce the risk of dangerous microbes entering. Excessive use of antibiotics or other chemicals can kill beneficial bacteria. As a result, dysbacteriosis develops (diarrhea, constipation, nausea) and the human immune system suffers.

Sergei

Bacteria harmful to human health. Most often, pathogenic microbes enter the human body through airborne droplets. But this is far from the only way to get infected. Dirty or stale food, bad water, poorly washed hands, various blood-sucking insects (fleas, lice, mosquitoes), a wound on the skin - all this can cause infection with bad microorganisms. Such organisms cause significant harm to health. Namely, they cause serious diseases:

What are the benefits and harms of bacteria

Elena

The harm from bacteria is very noticeable - many bacteria are sources of inflammation and infection. The deadly diseases typhoid and cholera, the serious diseases pneumonia and diphtheria are caused by bacteria, and it is not surprising that people are constantly looking for ways to combat them.
However, many bacteria are beneficial. Bacteria are useful, causing, for example, the fermentation of sweet juices or the ripening of cream. If bacteria did not decompose dead tissue, then the entire surface of the Earth would be covered with it. But most importantly, bacteria are involved in the formation of nitrates, which are necessary for plant life and, consequently, for our life.

Vladimir Kukuruzov

There are microorganisms that indirectly affect human life. They live in soils and water bodies and are engaged in the breakdown of organic waste, ensure the decay of dead plants, saturate the soil with essential minerals and oxygen. Thanks to them, the planet Earth does not lack oxygen.
Even in ancient times, people realized what invaluable benefits bacteria bring to a person in everyday life. Many foods cannot be made without the use of beneficial bacteria. Fermented milk products (kefir, yogurt), acetic acid, confectionery, cocoa, coffee are the result of the active life of microorganisms. Even the production of tanned leather or, for example, flax fiber is not complete without their participation.
fermented milk productsThere are many bacterial preparations that help control pests in agriculture and forestry. Some of these microscopic creatures are used for ensiling green fodder. And to purify wastewater, a special type of bacteria is used that decomposes organic residues and helps control the level of pollution of water bodies. And even in modern medicine, microorganisms are actively used for the manufacture of various vitamins, antibiotics and other drugs.
preparation with lactic acid bacteria Not all bacteria are beneficial and serve the benefit of people. There are also those that harm food, cause decay of organic matter and produce poison in the process. Eating poor-quality food leads to poisoning of the body. In some cases, the result is even sad - a fatal outcome. To protect yourself and your loved ones from the harm caused by bad bacteria, as well as maintain the natural balance of beneficial creatures in the body, you must:
Regularly eat fermented milk products enriched with bifido- and lactobacilli.
Eat only fresh and quality products.
Wash your hands before eating and thoroughly wash all fruits and vegetables.
Heat the meat.
Take antibiotics strictly as directed by your doctor. And try not to abuse various drugs. Otherwise, instead of benefit, you can cause significant harm to your health.
Compliance with these simple rules is the key to a healthy life.

How do bacteria enter the human body and what harm do they cause?

Valyusha

from the environment, for example, from dirty hands, towels, through the nose, mouth, skin, who has normal immunity - bacteria, in principle, are not terrible, and who has problems with it - various sores can occur due to bacteria - colds, acne, diarrhea etc.)

Dmitry Kalinkin

There is a hypothesis that all microorganisms are biorobots that perform the functions of repairing tissues, organs, cells, DNA
but not only repair, but also, in general, a change in the internal state of living beings, people, animals and plants, as well as unicellular ones. Viruses, like the smallest biorobots, are engaged in changes at the genetic level.
At the most rough level, helmpints are used.
That is, all microorganisms are a tool for managing the internal state of complex organisms on the part of the control function of NATURE. There is even a playful hypothesis that viruses are the driving force behind the evolution of living beings, which forced all living things to develop in order to ensure the life of viruses. (After all, they cannot live on their own.

Grigory Miroshin

Eternity…………

The danger of bacterial diseases was greatly reduced at the end of the 19th century with the invention of the vaccination method, and in the middle of the 20th century with the discovery of antibiotics.

useful; For thousands of years, humans have used lactic acid bacteria to produce cheese, yogurt, kefir, vinegar, and fermentation.

Currently, methods have been developed for the use of phytopathogenic bacteria as safe herbicides, entomopathogenic - instead of insecticides. The most widely used is Bacillus thuringiensis, which produces toxins (Cry-toxins) that act on insects. In addition to bacterial insecticides, bacterial fertilizers have found application in agriculture.

Bacteria that cause human disease are being used as biological weapons.

Due to their rapid growth and reproduction, as well as the simplicity of their structure, bacteria are actively used in scientific research in molecular biology, genetics, genetic engineering and biochemistry. Escherichia coli has become the best studied bacterium. Information about the processes of bacterial metabolism made it possible to produce bacterial synthesis of vitamins, hormones, enzymes, antibiotics, etc.

A promising direction is the enrichment of ores with the help of sulfur-oxidizing bacteria, the purification of soils and reservoirs contaminated with oil products or xenobiotics by bacteria.

Normally, from 300 to 1000 species of bacteria with a total weight of up to 1 kg live in the human intestine, and the number of their cells is an order of magnitude greater than the number of cells in the human body. They play an important role in the digestion of carbohydrates, synthesize vitamins, and displace pathogenic bacteria. It can be figuratively said that the human microflora is an additional "organ", which is responsible for protecting the body from infections and digestion.

it's not very short. but I think you can cut it however you like.

Karim Murotaliyev

Bacteria and man have coexisted with each other for millenniums. They bring enormous benefits to a person. Beneficial bacteria make up 99% of the total population that inhabit the human body and only 1% of them have a bad reputation. Due to the harm that bacteria cause to a person, any mention of them causes negative emotions. Bacteria are found in the air we breathe, in soil, in food and water, in plants, in our body, etc.

Rice. 1. Bacteria and man.

The first bacteria on planet Earth appeared billions of years ago, long before the appearance of plants, animals and humans. For millions of years, they, changing their habitat in an unfavorable climate, changed themselves, gradually improving their means of life support, and eventually inhabited the entire planet: oceans, soil, rocks, volcanoes and Arctic ice. The survival of bacteria was ensured by the presence of "jumping" genes, which they learned to pass on to each other along with the acquired achievements.

Rice. 2. Microbes are the real invisible masters of the Earth.

Rice. 3. About 70% of the living beings of the Earth are bacteria.

Bacteria and man: benefits for the human body

Bacteria have been living on planet Earth for more than 3.5 billion years. During this time they have learned a lot and adapted to a lot. Now they are helping people. Bacteria and man became inseparable. As scientists have calculated, the human body contains from 500 to 1000 different types of bacteria, or trillions of these amazing tenants, which is up to 4 kg of total weight. Up to 3 kilograms of microbial bodies is found only in the intestines. The rest of them are in the urogenital tract, on the skin and other cavities of the human body.

The human body is inhabited by both beneficial and harmful bacteria. The existing balance between the human body and bacteria has been polished for centuries. With a decrease in immunity, "bad" bacteria cause great harm to the human body. In some diseases, the process of replenishing the body with “good” bacteria is difficult.

Rice. 4. Bacteria inhabiting the oral cavity: Streptococcus mutants (green). Bacteroides gingivalis, causes periodontitis (purple). Candida albicus (yellow).

Rice. 5. The inner surface of the large intestine. Pink islets are clusters of bacteria.

Rice. 6. Bacteria in the duodenum (indicated in red).

Rice. 7. Bacteria (blue and green) on human skin (computer image).

Microbes fill the body of a newborn from the first minutes of his life and finally form the composition of the intestinal microflora by 10-13 years. Streptococci, lactobacilli, bifidobacteria, enterobacteria, fungi, intestinal viruses, non-pathogenic protozoa live in the intestine. Lactobacilli and bifidobacteria make up 60% of the intestinal flora. The composition of this group of bacteria is always constant, numerous and performs the main functions.

Rice. 12. Intestinal bacteria (red) in the duodenum.

A person owes the normal functioning of the body to bifidobacteria, lactobacilli, enterococci, Escherichia coli and bacteriods, which account for 99% of the normal intestinal microflora. 1% are representatives of opportunistic flora: clostridia, Pseudomonas aeruginosa, staphylococci, proteas, etc.

bifidobacteria

thanks to bifidobacteria, acetate and lactic acid are produced. By acidifying the habitat, they inhibit the growth of pathogenic bacteria that cause decay and fermentation;
thanks to bifidobacteria, the risk of developing food allergies in babies is reduced;
they provide an antioxidant and antitumor effect;
bifidobacteria are involved in the synthesis of vitamin C;
bifido- and lactobacilli take part in the processes of assimilation of vitamin D, calcium and iron.

Rice. 13. Bifidobacteria. 3D image.

coli

Special attention is paid to the representative of this genus Escherichia coli M17. It is able to produce the substance cocilin, which inhibits the growth of a number of pathogenic microbes.
With the participation of Escherichia coli, vitamins K, group B (B1, B2, B5, B6, B7, B9 and B12), folic and nicotinic acids are synthesized.

Rice. 14. E. coli. 3D image.

Rice. 15. Escherichia coli under a microscope.

Enterobacteria

Enterobacteria are actively involved in the restoration of intestinal microflora after taking antibiotics.

lactobacilli

Lactobacilli inhibit the growth of putrefactive and conditionally pathogenic microorganisms due to the formation of a number of antimicrobial substances.

Rice. 16. Lactobacilli (3D image).

The positive role of bacteria in the human body

With the participation of bifido-, lacto- and enterobacteria, vitamins K, C, group B (B1, B2, B5, B6, B7, B9 and B12), folic and nicotinic acids are synthesized.
Thanks to the intestinal microflora, undigested food components from the upper intestines are broken down - starch, cellulose, protein and fat fractions.
The intestinal microflora maintains water-salt metabolism and ionic homeostasis.
Due to the secretion of special substances, the intestinal microflora inhibits the growth of pathogenic bacteria that cause putrefaction and fermentation.
Bifido-, lacto- and enterobacteria take part in the detoxification of substances that enter from the outside and are formed inside the body itself.
The intestinal microflora plays an important role in restoring local immunity. Thanks to it, the number of lymphocytes, the activity of phagocytes and the production of immunoglobulin A increase.
Thanks to the intestinal microflora, the development of the lymphoid apparatus is stimulated.
Increases the resistance of the intestinal epithelium to carcinogens.
Microflora protect the intestinal mucosa and provide energy to the intestinal epithelium.
Regulates intestinal peristalsis.
The intestinal flora acquires the skills to capture and remove viruses from the host organism, with which it has been in symbiosis for many years.
Maintains the body's thermal balance. The microflora feeds on substances that are not digested by the enzymatic system of substances coming from the upper sections of the gastrointestinal tract. As a result of complex biochemical reactions, a huge amount of thermal energy is produced. Heat is carried throughout the body with blood flow and enters all internal organs. That is why a person always freezes when starving.
Regulates the reabsorption of components of bile acids (cholesterol), hormones, etc.

Rice. 17. Lactobacillus and Bifidobacterium bifidum cells.

Rice. 18. E. coli.

In diseases that reduce the body's immunity, intestinal diseases, long-term use of antibacterial drugs and in the absence of lactose in the human body, when the sugar contained in milk is not digested and begins to ferment in the intestine, changing the acid balance of the intestine, microbial imbalance occurs - dysbacteriosis (dysbiosis). Dysbacteriosis is characterized by the death of "good" bacteria and the increased growth of pathogenic microorganisms and fungi. In the intestines, the processes of putrefaction and fermentation begin to prevail. This is manifested by diarrhea and bloating, pain, loss of appetite, and then weight, children begin to lag behind in development, anemia and hypovitaminosis develop.

Bacteria and man will always coexist together. The health of every person is in his hands. If a person takes care of himself, then he will remain healthy, which means happy for many years.

Rice. 19. Bacteria and man. Together forever.

Many types of bacteria are useful and successfully used by humans.

Firstly, beneficial bacteria are widely used in the food industry.

In the production of cheese, kefir, cream, milk coagulation is necessary, which occurs under the action of lactic acid. Lactic acid is produced by lactic acid bacteria, which are part of the starter cultures and feed on the sugar contained in milk. Lactic acid itself promotes the absorption of iron, calcium, phosphorus. These beneficial elements help us fight infectious diseases.

In the production of cheese, it is pressed into pieces (heads). The cheese heads are sent to the ripening chambers, where the activity of various lactic and propionic acid bacteria included in its composition begins. As a result of their activity, the cheese "ripens" - it acquires a characteristic taste, smell, pattern and color.

For the production of kefir, a starter containing lactic acid bacilli and lactic acid streptococci is used.

Yogurt is a tasty and healthy fermented milk product. Milk for the production of yogurt must be of very high quality. It should have a minimum amount of harmful bacteria that can interfere with the development of beneficial yogurt bacteria. Yoghurt bacteria convert milk into yogurt and give it a distinctive flavor.

Rice. 14. Lactobacilli - lactic acid bacteria.

Lactic acid and yogurt bacteria entering the human body with food help to fight not only harmful bacteria in the intestines, but also viruses that cause colds and other infections. In the course of their life activity, these beneficial bacteria create such an acidic environment (due to the excreted metabolic products) that only a microbe very adapted to harsh conditions, such as E. coli, can survive next to them.

The activity of beneficial bacteria is used in the fermentation of cabbage and other vegetables.

Secondly, bacteria are used to leach ores in the extraction of copper, zinc, nickel, uranium and other metals from natural ores. Leaching is the extraction of minerals from ore that is not rich in them with the help of bacteria, when other methods of obtaining (for example, smelting the ore) are inefficient and expensive. Leaching is carried out by aerobic bacteria.

Thirdly, beneficial aerobic bacteria are used to clean wastewater from cities and industrial enterprises from organic remains.

The main purpose of such biological treatment is the neutralization of complex and insoluble organic substances of wastewater that cannot be extracted from it by mechanical treatment, and their decomposition into simple water-soluble elements.

Fourth, bacteria are used in the production of silk and leather processing, etc. Raw materials for the manufacture of artificial silk are produced by special transgenic bacteria. Technical lactic acid bacteria are used in the leather industry for swelling and deashing (treatment of raw materials from solid compounds), in the textile industry, as an auxiliary agent for dyeing and printing.

Fifth, bacteria are used to control agricultural pests. Agricultural plants are treated with special preparations that contain certain types of bacteria. Insects - pests, absorbing parts of plants treated with biological products, swallow bacterial spores with food. This leads to the death of pests.

sixth, bacteria are used to produce various medicines (for example, interferon) that kill viruses and support human immunity (protection).

And the last, harmful bacteria also have beneficial properties.

Decay bacteria (coprophytic bacteria) destroy the corpses of dead animals, leaves of trees and shrubs that have fallen to the ground, and the trunks of dead trees themselves. These bacteria are a kind of orderlies of our planet. They feed on organic matter and turn it into humus - a fertile layer of the earth.

Soil bacteria live in the soil and also provide many benefits in nature. Mineral salts, which are produced by soil bacteria, are then absorbed from the soil by plant roots. One cubic centimeter of the surface layer of forest soil contains hundreds of millions of soil bacteria.

Rice. 15. Clostridia - soil bacteria.

Bacteria also live in the soil, which absorb nitrogen from the air, accumulating it in their body. This nitrogen is then converted into proteins. After the death of bacterial cells, these proteins turn into nitrogenous compounds (nitrates), which are fertilizer and are well absorbed by plants.

Conclusion.

Bacteria are a large, well-studied group of microorganisms. Bacteria are found everywhere and a person meets with them in his life all the time. Bacteria can be beneficial to humans, and can become a source of dangerous diseases.

The study of the properties of bacteria, the fight against their harmful manifestations and the use of the beneficial properties of the vital activity of bacteria is one of the main tasks for humans.

6th grade student B _________________________________ / Yaroslav Shchipanov /

Literature.

1. Berkinblit M.B., Glagolev S.M., Maleeva Yu.V., Biology: Textbook for grade 6. – M.: Binom. Knowledge Lab, 2008.

2. Ivchenko, T. V. Electronic textbook “Biology: Grade 6. Living organism". // Biology at school. - 2007.

3. Pasechnik V.V. Biology. 6 cells Bacteria, fungi, plants: Proc. for general education textbook establishments, - 4th ed., stereotype. – M.: Bustard, 2000.

4. Smelova, V.G. Digital microscope at biology lessons // Publishing House "First of September" Biology. - 2012. - No. 1.

Bacteria appeared about 3.5-3.9 billion years ago, they were the first living organisms on our planet. Over time, life developed and became more complex - new, each time more complex forms of organisms appeared. Bacteria all this time did not stand aside, on the contrary, they were the most important component of the evolutionary process. It was they who first developed new forms of life support, such as respiration, fermentation, photosynthesis, catalysis ... and also found effective ways to coexist with almost every living being. Man is no exception.

But bacteria is a whole domain of organisms, with over 10,000 species. Each species is unique and followed its own evolutionary path, as a result, it developed its own unique forms of coexistence with other organisms. Some bacteria went into close mutually beneficial cooperation with humans, animals and other creatures - they can be called useful. Other species have learned to exist at the expense of others, using the energy and resources of donor organisms - they are commonly considered harmful or pathogenic. Still others have gone even further and have become practically self-sufficient, they receive everything they need for life from the environment.

Inside humans, as well as inside other mammals, lives an unimaginably large number of bacteria. There are 10 times more of them in our bodies than all the cells of the body combined. Among them, the vast majority are useful, but the paradox is that their vital activity, their presence inside us is a normal state of affairs, they depend on us, we, in turn, on them, and at the same time we do not feel any signs of this cooperation. Another thing is harmful, for example, pathogenic bacteria, once inside us, their presence immediately becomes noticeable, and the consequences of their activity can become very serious.

Beneficial bacteria

The vast majority of them are creatures living in symbiotic or mutualistic relationships with donor organisms (in which they live). Usually, such bacteria take on some of the functions that the host organism is not capable of. An example is the bacteria that live in the human digestive tract and process part of the food that the stomach itself is not able to cope with.

Some types of beneficial bacteria:

Escherichia coli (lat. Escherichia coli)

It is an integral part of the intestinal flora of humans and most animals. Its benefits can hardly be overestimated: it breaks down indigestible monosaccharides, promoting digestion; synthesizes vitamins of group K; prevents the development of pathogenic and pathogenic microorganisms in the intestine.

Closeup: colony of bacteria Escherichia coli

Lactic acid bacteria (Lactococcus lactis, Lactobacillus acidophilus, etc.)

Representatives of this order are present in milk, dairy and fermented products, and at the same time are part of the microflora of the intestines and oral cavity. Able to ferment carbohydrates and in particular lactose and produce lactic acid, which is the main source of carbohydrates for humans. By maintaining a constantly acidic environment, the growth of unfavorable bacteria is inhibited.

bifidobacteria

Bifidobacteria have the most significant effect on infants and mammals, accounting for up to 90% of their intestinal microflora. Through the production of lactic and acetic acids, they completely prevent the development of putrefactive and pathogenic microbes in the child's body. In addition, bifidobacteria: contribute to the digestion of carbohydrates; protect the intestinal barrier from the penetration of microbes and toxins into the internal environment of the body; synthesize various amino acids and proteins, vitamins of groups K and B, useful acids; promote intestinal absorption of calcium, iron and vitamin D.

Harmful (pathogenic) bacteria

Some types of pathogenic bacteria:

Salmonella Typhi

This bacterium is the causative agent of a very acute intestinal infection, typhoid fever. Salmonella typhi produces toxins that are dangerous only for humans. When infected, a general intoxication of the body occurs, which leads to severe fever, a rash throughout the body, in severe cases, to damage to the lymphatic system and, as a result, to death. Every year, 20 million cases of typhoid fever are recorded in the world, 1% of cases lead to death.

Salmonella typhi bacteria colony

Tetanus bacillus (Clostridium tetani)

This bacterium is one of the most persistent and at the same time the most dangerous in the world. Clostridium tetani produces an extremely toxic poison, tetanus exotoxin, which causes almost complete damage to the nervous system. People who become ill with tetanus experience the most terrible torment: all the muscles of the body spontaneously strain to the limit, powerful convulsions occur. Mortality is extremely high - on average, about 50% of those infected die. Fortunately, back in 1890, the tetanus vaccine was invented, it is given to newborns in all developed countries of the world. In underdeveloped countries, tetanus kills 60,000 people every year.

Mycobacteria (Mycobacterium tuberculosis, Mycobacterium leprae, etc.)

Mycobacteria are a family of bacteria, some of which are pathogenic. Various representatives of this family cause such dangerous diseases as tuberculosis, mycobacteriosis, leprosy (leprosy) - they are all transmitted by airborne droplets. Mycobacteria cause more than 5 million deaths each year.

What is bacteria

Bacteria in Greek means "stick". This name does not mean that harmful bacteria are meant.

Man and bacteria

The appearance of bacteria in the body

A newly born baby has a sterile intestine.

Beneficial bacteria

Useful bacteria are: lactic acid, bifidobacteria, E. coli, streptomycents, mycorrhiza, cyanobacteria.

Types of harmful bacteria

Bacteria can be gram-positive, gram-negative, rod-shaped.

Names of harmful bacteria

Table. Harmful bacteria for humans. Titles

Titles	Habitat	Harm
Mycobacteria	food, water	tuberculosis, leprosy, ulcer
tetanus bacillus	soil, skin, digestive tract	tetanus, muscle spasms, respiratory failure
Plague wand (considered by experts as a biological weapon)	only in humans, rodents and mammals	bubonic plague, pneumonia, skin infections
Helicobacter pylori	human stomach lining	gastritis, peptic ulcer, produces cytotoxins, ammonia
anthrax bacillus	the soil	anthrax
botulism stick	food, contaminated dishes	poisoning

Harmful bacteria are able to stay in the body for a long time and absorb useful substances from it. However, they can cause an infectious disease.

The most dangerous bacteria

And another bacterium that can lead to the death of a person is It causes tuberculosis, which is resistant to drugs. If you do not seek help in a timely manner, a person may die.

Measures to prevent the spread of infections

The second stage is the destruction of the ways through which harmful bacteria can be transmitted. To do this, carry out appropriate propaganda among the population.

Food facilities, reservoirs, warehouses with food storage are taken under control.

Bacteria are dangerous and useful, their role in human life

Bacterial infections are considered one of the most dangerous - humanity has been fighting pathogenic microorganisms for more than one century. However, not all bacteria are unambiguous enemies for humans. Many species are vital - they ensure proper digestion and even help the immune system defend itself against other microorganisms. MedAboutMe will tell you how to distinguish between bad and good bacteria, what to do if they are found in the analysis, and how to properly treat the diseases they cause.

Bacteria and man

It is believed that bacteria appeared on Earth more than 3.5 billion years ago. It was they who became active participants in creating suitable conditions for life on the planet, and throughout their existence they have been actively involved in important processes. For example, it is thanks to bacteria that the decay of the organic remains of animals and plants occurs. They also created fertile soil on Earth.

And since bacteria live literally everywhere, the human body is no exception. On the skin, mucous membranes, in the gastrointestinal tract, nasopharynx, urogenital tract, there are many microorganisms that interact with humans in different ways.

In the womb, the placenta protects the fetus from the penetration of bacteria, the population of the body occurs in the first days of life:

The first bacteria the child receives, passing through the birth canal of the mother.
Microorganisms enter the gastrointestinal tract through breastfeeding. Here, among more than 700 species, lactobacilli and bifidobacteria predominate (the benefits are described in the table of bacteria at the end of the article).
The oral cavity is inhabited by staphylococci, streptococci and other microbes, which the child also receives with food and in contact with objects.
On the skin, the microflora is formed from bacteria that predominate in the people around the child.

The role of bacteria for a person is invaluable, if already in the first months the microflora does not form normally, the child will lag behind in development and often get sick. After all, without symbiosis with bacteria, the body cannot function.

Beneficial and harmful bacteria

Everyone is well aware of the concept of dysbacteriosis - a condition in which the natural microflora in the human body is disturbed. Dysbacteriosis is a serious factor in lowering the immune defense, the development of various inflammations, disruption of the digestive tract and other things. The absence of beneficial bacteria contributes to the reproduction of pathogenic organisms, and fungal infections often develop against the background of dysbacteriosis.

At the same time, many pathogenic microbes live in the environment, which can cause serious illness. The most dangerous are those types of bacteria that in the process of life are capable of producing toxins (exotoxins). It is these substances that are today considered one of the most powerful poisons. Such microorganisms cause dangerous infections:

Botulism.
Gas gangrene.
diphtheria.
Tetanus.

In addition, the disease can be provoked by bacteria that live in the human body under normal conditions, and when the immune system is weakened, they begin to become more active. The most popular pathogens of this kind are staphylococci and streptococci.

Bacteria life

Bacteria are full-fledged living organisms with a size of 0.5-5 microns, which are able to actively multiply in a suitable environment. Some of them need oxygen, others do not. There are motile and non-motile types of bacteria.

Bacteria cell

Most bacteria living on Earth are single-celled organisms. Mandatory components of any microbe:

Nucleoid (nucleus-like region containing DNA).
Ribosomes (carry out the synthesis of proteins).
Cytoplasmic membrane (separates the cell from the external environment, maintains homeostasis).

Also, some bacterial cells have a thick cell wall, which additionally protects them from damage. Such organisms are more resistant to drugs and antigens that the human immune system produces.

There are bacteria with flagella (mototrichia, lophotrichia, peritrichia), due to which microorganisms are able to move. However, scientists have also recorded another type of movement characteristic of microbes - the sliding of bacteria. Moreover, recent studies show that it is inherent in those species that were previously considered immobile. For example, scientists from the University of Nottingham and Sheffield have shown that methicillin-resistant Staphylococcus aureus (one of the main representatives of the class of superbugs) is able to move without the help of flagella and villi. And this, in turn, significantly affects the understanding of the mechanisms of the spread of a dangerous infection.

Bacterial cells can be of the following forms:

Round (cocci, from other Greek κόκκος - "grain").
Rod-shaped (bacilli, clostridia).
Sinuous (spirochetes, spirilla, vibrios).

Many microorganisms are able to stick together in colonies, so more often scientists and doctors isolate bacteria not by the structure of the element, but by the type of compounds:

Diplococci are cocci connected in pairs.
Streptococci are cocci that form chains.
Staphylococci are cocci that form clusters.
Streptobacteria are rod-shaped microorganisms connected in a chain.

Reproduction of bacteria

The vast majority of bacteria reproduce by division. The rate of spread of the colony depends on the external conditions and the type of microorganism itself. So, on average, one bacterium is able to divide every 20 minutes - it forms 72 generations of offspring per day. For 1-3 days, the number of descendants of one microorganism can reach several million. In this case, the reproduction of bacteria may not be so fast. For example, the process of division of Mycobacterium tuberculosis takes 14 hours.

If the bacteria enter a favorable environment and have no competitors, the population grows very quickly. Otherwise, its number is regulated by other microorganisms. That is why the human microflora is an essential factor in its protection against various infections.

bacterial spores

One of the features of rod-shaped bacteria is their ability to sporulate. These microorganisms are called bacilli, and they include such pathogenic bacteria:

The genus Clostridium (cause gas gangrene, botulism, often cause complications during childbirth and after abortion).
The genus Bacillus (cause anthrax, a number of food poisonings).

Bacterial spores are, in fact, a conserved cell of a microorganism that can survive for a long time without damage, and is practically not subject to various influences. In particular, spores are heat-resistant, not damaged by chemicals. Often the only possible effect is ultraviolet rays, under which the dried bacteria can die.

Bacterial spores form when the microorganism is exposed to unfavorable conditions. It takes approximately 18-20 hours to form inside the cell. At this time, the bacterium loses water, decreases in size, becomes lighter, and a dense shell forms under the outer membrane. In this form, the microorganism can freeze for hundreds of years.

When the spore of a bacterium is exposed to suitable conditions, it begins to germinate into a viable bacterium. The process takes about 4-6 hours.

Types of bacteria

According to the influence of bacteria on humans, they can be divided into three types:

Pathogenic.
Conditionally pathogenic.
Non-pathogenic.

Beneficial bacteria

Non-pathogenic bacteria - those that never lead to disease, even if their numbers are large enough. Among the most famous species, lactic acid bacteria can be distinguished, which are actively used by humans in the food industry - for making cheeses, sour-milk products, dough and much more.

Another important species is bifidobacteria, which are the basis of the intestinal flora. In breastfed infants, they make up to 90% of all species living in the gastrointestinal tract. These bacteria for humans perform the following functions:

Provide physiological protection of the intestine from the penetration of pathogenic organisms.
They produce organic acids that prevent the reproduction of pathogenic microbes.
They help to synthesize vitamins (K, group B), as well as proteins.
Enhance the absorption of vitamin D.

The role of bacteria of this species is difficult to overestimate, because without them normal digestion is impossible, and hence the absorption of nutrients.

Opportunistic bacteria

As part of a healthy microflora, there are bacteria that are classified as opportunistic pathogens. These microorganisms can exist for years on the skin, in the nasopharynx or intestines of a person and not cause infections. However, under any favorable conditions (weakened immunity, microflora disturbances), their colony grows and becomes a real threat.

A classic example of an opportunistic bacterium is Staphylococcus aureus, a microbe that can cause over 100 different diseases, from boils on the skin to deadly blood poisoning (sepsis). At the same time, this bacterium is found in most people in various analyzes, but it still does not cause illness.

Among other representatives of the species of opportunistic microbes:

Streptococci.
Escherichia coli.
Helicobacter pylori (capable of causing ulcers and gastritis, but lives in 90% of people as part of a healthy microflora).

Getting rid of these types of bacteria does not make sense, since they are widespread in the environment. The only adequate way to prevent infections is to strengthen the immune system and protect the body from dysbacteriosis.

Pathogenic bacteria behave differently - their presence in the body always means the development of an infection. Even a small colony can cause harm. Most of these microorganisms secrete two types of toxins:

Endotoxins are poisons that are formed when cells are destroyed.
Exotoxins are poisons that bacteria produce during their life. The most dangerous substances for humans that can lead to fatal intoxication.

The treatment of such infections is aimed not only at the destruction of pathogenic bacteria, but also at the removal of the poisoning caused by them. Moreover, in the case of infection with microbes such as tetanus bacillus, it is the introduction of toxoid that is the basis of therapy.

Other known pathogenic bacteria include:

Salmonella.
Pseudomonas aeruginosa.
Gonococcus.
Pale treponema.
Shigella.
Tuberculosis bacillus (Koch's stick).

Classes of bacteria

Today there are many classifications of bacteria. Scientists divide them according to the type of structure, ability to move and other features. However, the Gram classification and the type of breathing remain the most important.

Anaerobic and aerobic bacteria

Among the diversity of bacteria, two large classes are distinguished:

Anaerobic - those that can do without oxygen.
Aerobic - those that need oxygen to live.

A feature of anaerobic bacteria is their ability to live in environments where other microorganisms do not survive. The most dangerous in this regard are deep contaminated wounds, in which microbes develop rapidly. The characteristic signs of the growth of the population and life of bacteria in the human body are as follows:

Progressive tissue necrosis.
Subcutaneous suppurations.
Abscesses.
Internal lesions.

Anaerobes include pathogenic bacteria that cause tetanus, gas gangrene, and toxic lesions of the gastrointestinal tract. Also, the anaerobic class of bacteria includes many opportunistic microbes that live on the skin and in the intestinal tract. They become dangerous if they get into an open wound.

Disease-causing aerobic bacteria include:

Tuberculosis bacillus.
Vibrio cholerae.
Tularemia stick.

The life of bacteria can proceed even with a small amount of oxygen. Such microbes are called facultative aerobic, salmonella and cocci (streptococcus, staphylococcus) are a striking example of the group.

In 1884, Danish physician Hans Gram discovered that different bacteria stained differently when exposed to methylene violet. Some retain color after washing, others lose it. Based on this, the following classes of bacteria were isolated:

Gram-negative (Gram-) - discoloring.
Gram-positive (Gram +) - staining.

Staining with aniline dyes is a simple technique that makes it possible to quickly reveal the characteristics of the bacterial membrane wall. For those microbes that do not stain by Gram, it is more powerful and durable, which means that it is more difficult to deal with them. Gram-negative bacteria are primarily more resistant to antibodies produced by the human immune system. This class includes microbes that cause such diseases:

Syphilis.
Leptospirosis.
Chlamydia.
meningococcal infection.
Hemophilus infection
Brucellosis.
Legionellosis.

The Gram+ class of bacteria includes the following microorganisms:

Staphylococcus.
Streptococcus.
Clostridia (causative agents of botulism and tetanus).
Listeria.
Diphtheria stick.

Diagnosis of bacterial infections

Correct and timely diagnosis plays an important role in the treatment of bacterial infections. It is possible to accurately determine the disease only after the analysis, but it can already be suspected by the characteristic symptoms.

Bacteria and viruses: features of bacteria and differences in infections

Most often, a person is faced with acute respiratory diseases. As a rule, cough, rhinitis, fever and sore throat are caused by bacteria and viruses. And although at certain stages of the disease they can manifest themselves in the same way, their therapy will still be radically different.

Bacteria and viruses behave differently in the human body:

Bacteria are full-fledged living organisms, large enough (up to 5 microns), capable of reproduction in a suitable environment (on mucous membranes, skin, in wounds). Pathogenic microbes secrete poisons that lead to intoxication. The same bacteria can cause infections of different localization. For example, Staphylococcus aureus affects the skin, mucous membranes, and can lead to blood poisoning.
Viruses are non-cellular infectious agents that can reproduce only inside a living cell, and in the external environment do not manifest themselves as living organisms. At the same time, viruses are always highly specialized and can only infect a specific type of cell. For example, hepatitis viruses can only infect the liver. Viruses are much smaller than bacteria, their size does not exceed 300 nm.

Today, effective drugs have been developed against bacteria -. But these drugs do not act on viruses, moreover, according to the World Health Organization, antibacterial therapy for ARVI worsens the patient's condition.

Symptoms of bacterial infections

Most often, seasonal respiratory infections develop under the influence of bacteria and viruses according to the following scheme:

The first 4-5 days manifest a viral infection.
On the 4-5th day, if the rules for the treatment of acute respiratory viral infections were not followed, a bacterial lesion joins.

Symptoms of a bacterial infection in this case will be:

Deterioration of the patient's condition after improvement.
High temperature (38°C and above).
Severe pain in the chest (a sign of the development of pneumonia).
Discoloration of mucus - greenish, white or yellowish discharge from the nose and in expectorated sputum.
Rash on the skin.

If it is possible to treat without the involvement of a doctor, since a viral infection resolves itself without complications in 4-7 days, then diseases caused by pathogenic bacteria must be consulted by a therapist or pediatrician.

Other bacterial infections are characterized by the following symptoms:

General deterioration.
A pronounced inflammatory process - pain in the affected area, hyperemia, fever.
Suppuration.

Methods of transmission of bacterial infections

Harmful bacteria enter the human body in many ways. The most common ways of infection:

Airborne.

Bacteria are found in the exhaled air, sputum of the patient, spread by coughing, sneezing and even talking. This route of transmission is typical for respiratory infections, in particular, whooping cough, diphtheria, scarlet fever.

Contact household.

Microbes get to a person through dishes, door handles, furniture surfaces, towels, phones, toys and more. Also, live bacteria and bacterial spores can stay in the dust for a long time. This is how tuberculosis, diphtheria, dysentery, diseases caused by aureus and other types of staphylococcus aureus are transmitted.

Alimentary (fecal-oral).

Bacteria enter the body through contaminated food or water. The transmission route is characteristic of gastrointestinal infections, in particular, typhoid fever, cholera, dysentery.

Sexual.

Infection occurs during sexual intercourse, this is how STIs are transmitted, including syphilis and gonorrhea.

Vertical.

The bacterium enters the fetus during pregnancy or childbirth. So the child can become infected with tuberculosis, syphilis, leptospirosis.

Deep wounds are dangerous for the development of infections - it is here that anaerobic bacteria, including tetanus bacillus, actively multiply. People with weakened immune systems are also more likely to contract a bacterial infection.

If you suspect the presence of pathogenic bacteria, the doctor may offer the following diagnostic options:

Smear on flora.

If a respiratory infection is suspected, it is taken from the mucous membranes of the nose and throat. The analysis is also popular for detecting sexually transmitted infections. In this case, the material is taken from the vagina, visceral canal, urethra.

Bacteriological culture.

It differs from a smear in that the taken biomaterial is not examined immediately, but is placed in an environment favorable for the reproduction of bacteria. After a few days or weeks, depending on the alleged pathogen, the result is evaluated - if there were harmful bacteria in the biomaterial, they grow into a colony. Bakposev is also good in that during the analysis, not only the pathogen is determined, but also its quantity, as well as the sensitivity of the microbe to antibiotics.

Blood analysis.

A bacterial infection can be detected by the presence of antibodies, antigens in the blood and by the leukocyte formula.

Today, biomaterial is often examined by PCR (polymerase chain reaction), in which infection can be detected even with a small number of microbes.

Positive test and bacterial infections

Since many bacteria are opportunistic and at the same time live in the body, on the mucous membranes and skin of the majority of the population, the results of the analysis must be able to correctly interpret. It must be remembered that the mere presence of bacteria in a person is not a sign of a bacterial infection and is not a reason to start treatment. For example, the norm for Staphylococcus aureus is 103–104. With these indicators, no therapy is required. Moreover, since the microflora of each person is individual, even if the values \u200b\u200bare higher, but there will be no symptoms of the disease, the indicators can also be considered normal.

An analysis for different types of bacteria is prescribed if there are signs of infection:

Bad feeling.
Purulent discharge.
Inflammatory process.
Greenish, white or yellow mucus from the nose and in the expectorated sputum.

A positive analysis for bacteria in the absence of symptoms is taken for control if microbes are detected in people from risk groups: pregnant women, children, people in the postoperative period, patients with reduced immunity and concomitant diseases. In this case, it is recommended to take several tests to see the growth dynamics of the colony. If the values do not change, then the immune system is able to control the reproduction of bacteria.

Bacteria in the nasopharynx

Bacteria in the nasopharynx can cause respiratory tract infections. In particular, they are the cause of tonsillitis, bacterial tonsillitis and pharyngitis, as well as sinusitis. Running infections can cause a lot of inconvenience, chronic inflammation, persistent rhinitis, headaches and more. Such diseases are especially dangerous because harmful bacteria can descend through the respiratory tract and affect the lungs - causing pneumonia.

bacteria in urine

Ideally, it is urine that should be free from various microorganisms. The presence of bacteria in the urine may indicate an incorrectly passed analysis (in which microbes got into the material from the surface of the skin and mucous membranes), in which case the doctor asks to be examined again. If the result is confirmed, and the indicator exceeds 104 CFU / ml, bacteriuria (bacteria in the urine) indicates such diseases:

Kidney damage, in particular, pyelonephritis.
Cystitis.
Urethritis.
Inflammatory process in the urinary canal, for example, as a result of blocking it with a calculus. Observed in urolithiasis.
Prostatitis or prostate adenoma.

In some cases, bacteria in the urine are found in diseases that are not associated with a local infection. A positive analysis can be with diabetes mellitus, as well as a generalized lesion - sepsis.

Normally, the gastrointestinal tract is inhabited by colonies of various bacteria. In particular, there are:

Bifidobacteria.
Lactic acid bacteria (lactobacilli).
Enterococci.
Clostridia.
Streptococci.
Staphylococci.
Escherichia coli.

The role of the bacteria that make up the normal microflora is to protect the intestines from infections and ensure normal digestion. Therefore, often the biomaterial from the intestine is examined precisely because of the suspicion of dysbacteriosis, and not for the presence of pathogenic microorganisms.

However, some pathogenic bacteria can cause severe diseases, namely when they enter the gastrointestinal tract. Among these diseases:

Salmonellosis.
Cholera.
Botulism.
Dysentery.

bacteria on the skin

On the skin, as well as on the mucous membranes of the nasopharynx, in the intestines and genital organs, the balance of microflora is normally established. Bacteria live here - more than 100 species, among which epidermal and Staphylococcus aureus, streptococci are often found. With reduced immunity, and especially in children, they can provoke skin lesions, cause suppuration, boils and carbuncles, streptoderma, panaritium and other diseases.

In adolescence, the active reproduction of bacteria leads to acne and acne.

The main danger of microbes on the skin is the possibility of their entry into the bloodstream, wounds and other damage to the epidermis. In this case, harmless microorganisms on the skin can cause serious illness, even cause sepsis.

Diseases caused by bacteria

Bacteria are the cause of infections throughout the body. They affect the respiratory tract, cause inflammatory processes on the skin, cause diseases of the intestines and the genitourinary system.

Diseases of the respiratory tract and lungs

Angina

Angina is an acute lesion of the tonsils. The disease is typical for childhood.

Pathogen:

Streptococci, rarely staphylococci and other forms of bacteria.

Typical symptoms:

inflammation of the tonsils with a whitish coating on them, pain when swallowing, hoarseness, high fever, no rhinitis.

Disease risk:

if a sore throat is not treated well enough, rheumatoid heart disease can become a complication - harmful bacteria spread through the blood and lead to heart valve defects. As a result, heart failure may develop.

Whooping cough is a dangerous infectious disease that mainly affects children. Highly contagious, the bacterium is transmitted by airborne droplets, therefore, without a sufficient level of immunization of the population, epidemics are easily caused.

Pathogen:

Bordetella pertussis.

Typical symptoms:

the disease at first proceeds like a common cold, later a characteristic paroxysmal barking cough appears, which may not go away for 2 months, after an attack the child may vomit.

Disease risk:

Whooping cough is most dangerous for children of the first year of life, as it can cause respiratory arrest and death. Typical complications are pneumonia, bronchitis, false croup. From severe coughing attacks, it is extremely rare for a cerebral hemorrhage or pneumothorax to occur.

Pneumonia

Inflammation of the lungs can be caused by bacteria and viruses, as well as some fungi. Bacterial pneumonia, the most common complication of viral respiratory infections, can develop after the flu. Also, the multiplication of bacteria in the lungs is typical for bedridden patients, the elderly, patients with chronic lung diseases and respiratory disorders, with dehydration.

Pathogen:

Staphylococci, pneumococci, Pseudomonas aeruginosa and others.

Typical symptoms:

severe fever (up to 39 ° C and above), cough with copious moist greenish or yellowish sputum, chest pain, shortness of breath, feeling short of breath.

Disease risk:

depends on the pathogen. With insufficient treatment, respiratory arrest and death are possible.

Tuberculosis

Tuberculosis is one of the most dangerous lung diseases that is difficult to treat. In Russia, tuberculosis has been a socially significant disease since 2004, since the number of infected people is much higher than in developed countries. Back in 2013, up to 54 cases of infection per 100,000 people were recorded.

Pathogen:

mycobacterium, Koch's bacillus.

Typical symptoms:

the disease may not manifest itself for a long time, then a cough occurs, a general malaise, a person loses weight, a subfebrile temperature (37-38 ° C) is observed for a month or more, a painful blush. Later, hemoptysis and severe pain appear.

Disease risk:

features of the bacteria that cause tuberculosis is the development of resistance to antibiotics. Therefore, the infection is difficult to treat and can lead to death or disability. Common complications are heart disease.

Diphtheria is an infectious disease that in 90% of cases affects the upper respiratory tract. Diphtheria is especially dangerous for young children.

Pathogen:

Corynebacterium diphtheriae (Leffler's bacillus).

Typical symptoms:

pain when swallowing, hyperemia of the tonsils and specific white films on them, swollen lymph nodes, shortness of breath, high fever, general intoxication of the body.

Disease risk:

Without timely treatment, diphtheria is fatal. The bacterial cell is capable of producing exotoxin, so the sick person can die from poisoning, in which the heart and nervous system are affected.

Intestinal infections

salmonellosis

Salmonellosis is one of the most common intestinal infections that can occur in different forms. Sometimes bacteria cause severe lesions, but there are times when the disease is mild or no symptoms at all.

Pathogen:

Salmonella.

Typical symptoms:

high temperature (up to 38-39 ° C), chills, abdominal pain, vomiting, diarrhea, severe intoxication of the body, in which a person sharply weakens.

Disease risk:

Depending on the form of the course, in severe infections, bacterial toxins can lead to kidney failure or peritonitis. Children are at risk of dehydration.

Dysentery

Dysentery is an intestinal infection that affects people of all ages. Most often recorded in the summer hot period.

Pathogen:

4 types of Shigella bacteria.

Typical symptoms:

Loose stools of dark green color with impurities of blood and pus, nausea, headaches, loss of appetite.

Disease risk:

dehydration, which leads to the attachment of various inflammations, as well as intoxication of the body. With proper treatment, good immunity and sufficient fluid intake, the life of Shigella bacteria stops in 7-10 days. Otherwise, a serious complication is possible - intestinal perforation.

Gonorrhea

Gonorrhea is transmitted exclusively through sexual contact, but in rare cases, the infection can be passed from mother to child during childbirth (the baby develops conjunctivitis). The bacteria that causes gonorrhea can grow in the anus or throat, but it most often affects the genitals.

Pathogen:

Gonococcus.

Typical symptoms:

possible asymptomatic course of the disease: in men in 20%, in women - more than 50%. In the acute form, there are pains during urination, white-yellow discharge from the penis and vagina, burning and itching.

Disease risk:

If left untreated, the infection can cause infertility and can also damage the skin, joints, cardiovascular system, liver, and brain.

Syphilis

Syphilis is characterized by slow progression, symptoms appear gradually and do not develop quickly. The characteristic course of the disease is an alternation of exacerbations and remissions. Household infection, many doctors question, in the vast majority of cases, bacteria are transmitted to humans sexually.

Pathogen:

Pale treponema.

Typical symptoms:

at the first stage, an ulcer appears on the genitals, which heals on its own in 1-1.5 months, an increase in lymph nodes is observed. After, after 1-3 months, a pale rash appears all over the body, the patient feels weak, the temperature may rise, the symptoms resemble the flu.

Disease risk:

pathogenic bacteria eventually lead to the development of tertiary syphilis (30% of all infected), which affects the aorta, brain and back, brain, bones and muscles. Perhaps the development of damage to the nervous system - neurosyphilis.

Chlamydia

Chlamydia is a sexually transmitted infection that is often asymptomatic. In addition, pathogenic bacteria are difficult to detect; PCR analysis is prescribed for diagnosis.

Pathogen:

Chlamydia.

Typical symptoms:

in the acute form, discharge from the genital organs (usually transparent), pain during urination, blood discharge are observed.

Disease risk:

in men - inflammation of the epididymis, in women - inflammation of the uterus and appendages, infertility, Reiter's syndrome (inflammation of the urethra).

Meningococcal infection

Meningococcal infection is a group of diseases caused by one pathogen, but occurring in different forms. A person may be an asymptomatic carrier of the bacterium, and in other cases, the microbe causes a generalized infection leading to death.

Pathogen:

Meningococcus.

Typical symptoms:

vary with the severity of the disease. The infection can manifest itself as a mild cold, in severe cases, meningococcemia develops, characterized by an acute onset of the disease, the appearance of a red rash (does not disappear with pressure), the temperature rises, confusion is observed.

Disease risk:

in severe form, tissue necrosis develops, gangrene of the fingers and extremities, and brain damage are possible. With the development of infectious-toxic shock, death quickly occurs.

Tetanus

Tetanus is a dangerous infection that develops in wounds on the skin. The causative agent forms spores of bacteria, in the form of which it is found in the external environment. When it enters the wound, it quickly germinates. Therefore, any serious injury requires the prevention of infection - the introduction of tetanus toxoid.

Pathogen:

Tetanus stick.

Typical symptoms:

tetanus affects the central nervous system, at first it is manifested by tonic tension of the jaw muscles (it is difficult for a person to speak, open his mouth), later it spreads to the whole body, the patient arches due to muscle hypertonicity, and at the end respiratory failure develops.

Disease risk:

the main danger is the toxin that the bacterium secretes, it is he who leads to severe symptoms. As a result of poisoning, tonic tension of all muscles occurs, including the diaphragm and intercostal muscles, as a result of which a person cannot breathe and dies from hypoxia.

Treatment of bacterial diseases

Any bacterial infection needs planned treatment, because bacteria can cause serious damage to the body. Only the doctor chooses the appropriate treatment regimen, which depends not only on the type of disease, but also on the severity of the course.

Antibiotics

Antibiotics are considered the mainstay of treatment for all infections caused by harmful bacteria. Since the discovery of penicillin in the 1920s, many diseases have been moved from fatal to curable. The number of complications after operations has decreased, and, from which every fourth person died, remained a dangerous disease only for people from risk groups.

Modern antibiotics can be divided into two groups:

Bactericidal - kill pathogenic bacteria.
Bacteriostatic - slow down the growth, stop the reproduction of bacteria.

The former have a more pronounced effect, however, it is the drugs from the second group that are prescribed more often, since, as a rule, they cause fewer complications.

It is also customary to divide drugs according to the spectrum of action:

Broad-spectrum antibiotics (penicillins, tetracyclines, macrolides) are used to kill different types of bacteria. They are effective in the case when treatment needs to be started urgently, even before the tests. Penicillins are most commonly prescribed for respiratory bacterial infections.
Antibiotics that are active against a limited number of bacterial species (often prescribed for tuberculosis and other specific infections).

Any antibiotics must be taken in a course, because if treatment is interrupted, the remaining living bacteria quickly restore the colony.

Problems in the use of antibiotics

Despite the widespread use of antibiotics, doctors today are looking for alternative drugs to treat bacterial infections. This is due to several significant disadvantages of these drugs:

Development of resistance in bacteria.

Many microorganisms have developed defense mechanisms against drugs, and the use of classical antibiotics is no longer effective. For example, first-generation penicillins, which actively fought against staphylococci and streptococci, are not used today. Staphylococcus aureus has learned to synthesize the enzyme penicillinase, which destroys the antibiotic. Of particular danger are new strains of bacteria that have developed resistance to the latest generation of drugs - the so-called superbugs. The most famous of these is methicillin-resistant Staphylococcus aureus. Also, Pseudomonas aeruginosa and enterococci quickly develop resistance.

The use of broad-spectrum antibiotics leads to dysbacteriosis.

After such treatment, the balance of microflora is significantly disturbed, complications often develop, the body is weakened not only by the disease, but also by the action of drugs. The use of medicines is limited among certain population groups: pregnant women, children, patients with liver and kidney damage, and other categories.

bacteriophages

An alternative to antibiotics could be bacteriophages, viruses that kill a specific class of bacteria. Among the advantages of such drugs:

Low likelihood of developing resistance, since bacteriophages are organisms that have lived on Earth for several billion years and continue to infect bacterial cells.
They do not violate the microflora, since they are specialized medicines - effective only in relation to a specific type of microorganisms.
Can be used by people at risk.

Preparations containing bacteriophages are already available in pharmacies today. But still, such therapy is losing to antibiotics. Many diseases require immediate treatment, which means that broad-spectrum drugs are needed, while bacteriophages are highly specialized - they can be prescribed only after the pathogen has been identified. In addition, currently known viruses are not able to destroy such a large list of pathogenic bacteria as antibiotics.

Other treatments

WHO does not recommend the use of antibiotics for all types of bacterial infections. In the event that the microbe does not have a high pathogenicity, and the disease proceeds without complications, symptomatic treatment is sufficient - the use of antipyretics, painkillers, vitamin complexes, heavy drinking and other things. Often the immune system itself can suppress the reproduction of a colony of pathogenic microorganisms. However, in this case, the patient must be under the supervision of a doctor who will decide on the appropriateness of a particular method of therapy.

Effective vaccines have been developed for many deadly bacterial infections. Vaccinations are recommended for the following diseases:

Tuberculosis.
Haemophilus infection.
Pneumococcal infection.
Diphtheria (toxoid is used - a vaccine that helps produce antibodies to the toxin of the bacterium).
Tetanus (toxoid is used).

Bacteria, nutrition and digestion

The live bacteria in foods alone can restore the gut microflora, help the digestive tract, and get rid of toxins. Others, on the contrary, getting into the digestive tract with food, cause dangerous infections and serious poisoning.

Pathogenic bacteria often multiply in products with violations of storage rules. And breeding anaerobic bacteria are especially dangerous here, which easily increase their numbers even in goods in sealed packaging and canned food.
Another way of food contamination is through unwashed hands or equipment (knives, cutting boards, etc.). Therefore, food poisoning is easy to get after street food, which was prepared without observing sanitary standards.
Insufficient heat treatment or its absence also increases the likelihood of the reproduction of various pathogenic forms of bacteria.

Medicines with live bacteria

Preparations with beneficial live bacteria are often recommended by nutritionists for various disorders of the gastrointestinal tract. They help with bloating, flatulence, heaviness, poor digestion of food, frequent poisoning.

In the event that dysbacteriosis is severe, the doctor may recommend a course of drugs to restore microflora.

Probiotics are products that contain live beneficial bacteria.

The drug is available in capsules with a shell that protects the colonies of microorganisms and helps to deliver them to the intestines in a living form.

Prebiotics are carbohydrate preparations that contain nutrients for beneficial bacteria.

Such drugs are prescribed if the intestines are inhabited by bifidus and lactobacilli, but their colonies are not large enough.

Lactic acid bacteria are an extensive group of microorganisms that are able to process glucose with the release of lactic acid. In fact, this means that it is precisely these microbes that are involved in the process of fermenting milk - with their help, all fermented milk products are created. Food does not spoil longer precisely thanks to lactic acid bacteria - the acidic environment that they create prevents the growth of pathogens. They exhibit the same protective functions in the human intestine.

The main products in which lactic acid bacteria are present:

Yogurt without additives.
Starter cultures, kefir and other fermented milk drinks.
acidophilus milk.
Hard cheeses.
Sauerkraut.

Tables of the main bacteria

Pathogenic bacteria

Bacteria in the table are presented by the main types of microbes that can cause disease. However, many of them also include non-pathogenic or opportunistic bacteria.

Name	bacteria	Type of breath	Diseases caused by bacteria
Staphylococci		Facultative anaerobes	Staphylococcus aureus provokes most purulent diseases. Including: skin lesions, pneumonia, sepsis. Staphylococcus epidermidis causes purulent complications in the postoperative period, and saprophytic - cystitis and urethritis (bacteria are found in the urine).
streptococci		Facultative anaerobes	Scarlet fever, rheumatism (acute rheumatic fever), tonsillitis, pharyngitis, pneumonia, endocarditis, meningitis, abscess.
Clostridia		anaerobic bacteria	Bacteria can be part of a healthy microflora. At the same time, some species are able to secrete the strongest known poison - exotoxin botulinum toxin. Clostridia are the causative agents of tetanus, gas gangrene, and botulism.
		Aerobes, facultative anaerobes	Certain types of bacteria cause anthrax and intestinal infections. The genus also includes Escherichia coli - a representative of healthy microflora.
Enterococci		Facultative anaerobes	Urinary tract infections, endocarditis, meningitis, sepsis.

Beneficial bacteria

The table of bacteria represents the types of microbes that are vital to humans.

Name	bacteria shape	Type of breath	Benefits for the body
bifidobacteria		Anaerobes	Human bacteria, which are part of the intestinal and vaginal microflora, help normalize digestion (drugs with bifidobacteria are prescribed for diarrhea), assimilate vitamins. The peculiarity of bacteria is that they prevent the reproduction of staphylococci, shigella, candida fungus.
	Cocci, sticks	Aerobes requiring reduced oxygen concentration (microaerophilic bacteria)	A group of bacteria that is united by one characteristic - the ability to cause lactic acid fermentation. Used in the food industry, are part of probiotics.